I did a bad thing

Monday was such a beautiful day, I thought I'd clean up the engine on my
trusty '90 V8Q. The engine was cold. But this time I removed the Air intake
Shroud which covers the intake manifold, taking care to cover the air filter
with a plastic bag (confirmed - no water ingress there). I sprayed the
engine liberally with gunk engine cleaner and then hosed it off. 20 min.
later went for a test drive and ar stumbled a lot, cuting out. I correctly
surmised that the distributor caps may have ahd some water ingress, removed
and cleaned them. Also checked the spark plugs (some carbon deposits,
cleaned, regapped and replaced). After I put it all together I had same
problem. Engine cutting out while accelerating, no trans downshifts, check
engine light coming on, staying on, then turning off again. When on, car
whould not downshift (staying in 3rd gear like limp-home mode). Hooked up
timing light to each plug wire -O.K. Let car sit overnight, drove first
thing this morning, and everything seemed O.K. Had breakfast, and then
problem started all over again as I drove to work! Any Ideas? Seems like
fuel cutoff when accelerating, then back on again (poss Hall sending unit?).
I'd like to check it over again when I get home tonight before I have to
bring it into the shop. Where are the hall sending units on this engine,
anyway. Any help would be much appreciated.
Anxious Ingo